Apparatus for evaporating liquids.



PATENTED JULY 12, 1904.

M. EKENBERG. APPARATUS FOR EVAPORATING LIQUIDS.

APPLICATION FILED NOV. 4, 1903.

N0 MODEL.

INVENTOH WITNESSES: 4 1m No. 764,995. Patented July 12, 1904.

UNITED STATES PATENT OFFICE.

MARTIN EKENBERG, OF STOCKHOLM, SWEDEN, ASSIGNOR TO MARTIN EKENBERGSAKTIEBOLAG, OF STOCKHOLM, SWEDEN.

APPARATUS FOR EVAPORATING LIQUIDS.

SPECIFICATION forming part of Letters Patent N 0. 764,995, dated July12, 1904. Application filed November 4, 1903. Serial No. 179,763. (Nomodel.)

To aZZ whom, it may concern: g ti i th 50 question of milk, to pre- Beit known that I, MARTIN EKENRERG, a liminarily concentrate the liquid ina special subject of the King of Sweden and Norway, apparatus, whichfact has caused many disand a resident of Odengatan 40, Stockholm,advantages and unnecessary expense, or the in the Kingdom of Sweden,have invented wall of the pan has been provided with aheatcertain newand useful Improvements in Aping device, in consequence of which aseries paratus for Concentrating and Evaporating of other disadvantageshave arisen. In order Liquids, of which the following is a specifitoremove these disadvantages, an apparatus cation, reference being hadtherein to the acin accordance with this invention is employed,companying drawings. whereby without exterior heating heat is Thisinvention relates to an apparatus for continually imparted to the liquidin the pan 6O concentrating emulsions, solutions, and the without takinginto consideration the thin like in a vacuum or under ordinary atmosfilmbeing evaporated to a dry condition, the pheric pressure simultaneouslywith evaporasaid heat being conducted to a surface of tion, which isproceeded with to such an eX- the same, which surface is continuallybeing tent that a dry residue is obtained, which is renewed. This iseffected by the fact that 5 collected as a useful final product. As anexthe liquid through a circulating movement ample of such manufacture,may be mentioned is continually caused to spread itself in a thin theevaporation of skim-milk in large quan: layer over such surfaces of theaforesaid rotities for the production of milk-powder, to tary body,which need not or cannot be emwhich production the following descriptionployed for the evaporating of the liquid to a 7 especially relates. Theevaporation is efi'ected dry condition. If thus for practical reasons ina pan, in which a suitably-heated rotating viz., in order to avoid theuse of too large an body is mounted and dips into the liquid, theapparatus-the surface of the rotary body peripheral speed of the saidbody being so cannot be made verylarge, the effectintended regulatedthat a dry film is formed upon the is still obtained-viz., by the liquidbeing surface of the same during the revolution, brought intocirculation and caused to flow the said film being removed from thissurface constantly over the heated surface-so that by means of suitablescrapers or the like. the liquid surface is' renewed at every mo- Thetemperature of the rotary body must not ment. A preliminaryconcentration is thus greatly exceed the boiling-point of the liquid,not necessary, and the entire evaporating and as the product mayotherwise be damaged and drying process can be effected in one and thethe body must rotate slowly in order that the same apparatus. Theapparatus is shown in liquid taken up by its surface may have time tothe accompanying drawings. evaporate. The evaporation may be hastenedFigure 1 shows the apparatus in vertical by powerfully drawing off thegenerated vasection through the shaft of the rotary body, 5 por from thepan; but in spite of this no and Fig. 2 shows the same in verticalcrossgreater speed of the rotary body and a corresection on the line a3/ in Fig. l. sponding greater effect can be obtained. Al- In the pan 1is rotatively mounted a hollow though an evaporation resulting indryness is shaft 2, which carries the rotary body 3, concertainlyeifected in the said manner, yet the sisting of a cylindrical drum withdeeply bent- 9 evaporation will take place if no other means in orcupped end plates 4. Steam or other than those specified for effectingthe same be heating medium is led in through the shaft employedcomparatively slowly, as any prefrom the one end and out through theother, liminary concentrating of the liquid introas shown by the arrows,so that the cylindrical duced into the pan will scarcely take place inpart, as well as the end plates, are heated from the pan. Hitherto ithas therefore been necwithin. In the rotary body is fitted acylinessary, as a rule, in order to attain an apprecidricalpartition-wall 12. This leaves an openable effect per unit ofheating-surface at the ing at each end against the inside of the body oris provided there with holes or the like, so that free communicationexists from the one side to the other side of the same. The shaft 2 hasan enlargement 13 and is within the latter divided by a partition orcross wall 141. On one side of the latter the shaft is provided withlateral openings 15 and on the other side with tubes 16, extendingradially from the shaft and to which the wall 12 is fixed. These tubesput the inside of the shaft in communication with. the chamber outsidethe Wall 12 in the body. The heating medium passes into the drum throughthe openings 15, thence extends on both sides to the inside of the wall12 and proceeds further over the edge of the wall 12 to the tubes 16.Through the tubes and shaft the heating medium escapes. The liquid to beevaporated is introduced through a pipe 5 by means of a pump or thelike. The liquid introduced is kept in constant circulation by a rotarypump 6. The outlet-pipe extending from the latter is divided into twobranches .7 8 outside the apparatus, which pipes enter the vessel andare so bent that they follow the shape of their respective plates 4:, asshown in the drawings. The branches of the pipe are provided with anumber of holes formed in the side facing the walls, through which theliquid in finelyspread jets issues toward the hot end plates 4:, inorder to run down the same and assemble on the bottom of the pan. Theliquid passes from here back again to the pump through the tube 9 inorder to be again sent into the apparatus, as shown by the arrows. Thepipe 9 is placed at such a level that a part of the liquid remains onthe bottom of the pan, into which the body 1 dips, as shown in Fig. 1.The evaporation to dryness takes place on the cylindrical outsidesurface of the rotary body 3 4c, and the dry mass is scraped off by ascraper 10 and falls into a delivery-chamber 11. As stated above, thebody 1 must not rotate faster than is necessary for the thin film takenup to be dried by the time it arrives at the scraper 10. Even if theliquid-level in the pan is so high that the end plates are also wet thecoat of liquid on the latter effected,

if required, by the aid of attached wings or the like should be verygently replenished or renewed. By means of the circulation device,consisting of the pump 6 and the pipe system 7 8 9, the change ofliquid-supply is caused to take place from fifty to one hundred timesfaster under continuous supply of heat passing through the metal endplate. By this arrangement the same results are obtained as with a muchlarger apparatus not provided with such arrangements in spite of theapparatus not being heated from outside. If the apparatus is to beemployed for concentration only, the body 3 1 is set in such rapidrotation that evaporation to a dry condition will not have time to takeplace, a suitable outlet for the concentrated liquid being provided.

The principal feature of the invention is the constant flowing of thecirculating liquid over a free surface not used for evaporation to a drycondition, such as the side walls, the end walls, and the like of theheated rotary body. The means for effecting circulation can obviously beeasily varied and arranged at different places-e. g. entirely within thereceptacle. The liquid may also be spread on the cylindrical outside ofthe drum somewhat above the point where it comes up out of the liquid ordips into the same, in the latter case consequently after the drum hasbeen freed from the dry mass.

Having now described my invention,'what I claim as new, and desire tosecure by Letters Patent, is

1. An apparatus for concentrating a liquid substance in vacuum or underordinary atmospheric pressure comprising a heated, rotating body, andmeans for continuously circulating said liquid and throwing it in jetsonto the upper part of the hot surface of said body.

2. An apparatus for the purpose specified, having a rotating body 3, andcirculating means with perforated branches from which the liquid to beconcentrated is thrown on the rotating body.

3. An apparatus for the purpose specified, having a vacuum-pan 1, arotating body 3 therein, and a circulating device, including a pump, forthrowing the liquid on the surface of said rotating body.

4. An apparatus for the purpose specified, having a liquid-receptacle, arotating body therein, means for heating said body, a circulating-pump6, a pipe connecting said receptacle with one side of the pump, a pipefrom the delivery side of the pump having perforated branches 7 and 8,said branches being disposed to discharge the liquid jet-like onto thesurface of the rotating body, and a pipe which supplies the liquid to becondensed to the said receptacle.

In witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

MARTIN EKENBERG WVitnesses:

AUG. SORENSEN, ERNST SVANQVIST.

